CFA Continuous Flight Auger Piling

This piling system is fast and economical. It has no vibration and limited noise levels.  However, it does have some limiting features.

Positive Features

• High production levels are attainable in suitable soil conditions
• The system is economical in suitable soil profiles
• Noise levels are low and limited to the engine noise of the piling rigs
• There is no vibration associated with CFA piles

Other Considerations

• In sandy soils below the water-table there is a reduction in soil strength in the immediate vicinity of the pile due to the drilling operation.  As a result of this, the load / deflection performance of a CFA pile is inferior to that of a driven pile
• Soil falling off the flight can contaminate the concrete / grout of the pile shaft
• CFA piles have to be cast to ground level.  This results in waste of concrete and excess trimming if there are deep cut-off levels
• There is very limited indication of soil strength during the drilling operation

The maximum depth of CFA piles is 30 metres at present and the recommended maximum rake 1:10.